Thrust reverser

ABSTRACT

A THRUST REVERSER FOR A GAS TURBINE ENGINE COMPRISES AN ANNULAR DUCT ADAPTED TO HAVE GASES FROM THE ENGINE PASS THERETHROUGH AND DEFINED BY RADIALLY INNER AND RADIALLY OUTER WALLS, THE RADIALLY OUTER WALL HAVING A CIRCUMFERENTIALLY EXTENDING OPENING, A PLURALITY OF ANGULARLY SPACED APART FLAPS MOVABLE BETWEEN A FIRST POSITION IN WHICH THEY CLOSE THE SAID OPENING AND A SECOND POSITION IN WHICH THEY EXTEND ACROSS AND AT LEAST PARTIALLY CLOSE THE ANNULAR DUCT TO THE REAR OF THE OPENING, EACH FLAP COMPRISING FRONT AND REAR FLAP PORTIONS, THE FRONT FLAP PORTION BEING FOLDED IN FRONT OF THE REAR PORTION IN THE ANNULAR DUCT WHEN THE FLAPS ARE IN THE SECOND POSITION.

Sept 28 1971 R. H. coLLEY 3,608,314

THRUST REVERSER Filed Aug. 25, 1969 2 Sheets-Sheet 1 Inventar fawn/v f/Af CoLs/f Wj LW A Morney S V R. H. COLLEY THRUST REVERSER Sept. 28, 1971 2 Sheets-Sheet 2 Filed Aug. 25, 1969 L mm um SJNQ wv mm um mm u... wm. mv b m v//f/f/wfy N n mqv/ m wm!! Mlm@ United States Patent Oihce 3,608,314 Patented Sept. 28, 1971 U.S. Cl. 60-226 11 Claims ABSTRACT OF THE DISCLOSURE A thrust reverser for a gas turbine engine comprises an annular duct adapted to have gases from the engine pass therethrough and defined by radially inner and radially outer walls, the radially outer wall having a circumferentially extending opening, a plurality of angularly spaced apart flaps movable between a rst position in which they close the said opening and a second position in which they extend across and at least partially close the annular duct to the rear of the opening, each tlap comprising front and rear ap portions, the front flap portion being folded in front of the rear flap portion in the annular duct when the aps are in the second position.

This invention relates to thrust reversers for gas-turbine jet propulsion engines, and particularly to thrust reversers for gas turbine jet propulsion engines having ducted fans.

The invention provides a thrust reverser for a gas turbine engine comprising an axially extending duct adapted to have gases from the engine pass therethrough; wall structure of the duct having a circumferentially extending opening; a plurality of flaps angularly spaced apart around the duct and having respective front and rear ap portions movable between respective rst positions in which they close the opening, and respective second positions in which they extend across and at least partially close the duct to the rear of the opening, the front iiap portions being disposed in front of the rear ap portions when in the said second positions; and first means pivotally connecting the front flap portions to their respective rear iiap portions, the connecting means being slidable along the rear flap portions.

The front flap portions may be interconnected with the rear iiap portions for relative pivoting and sliding movement.

The rear ap portion may be pivotally connected to a xed portion of the radially outer wall to the rear of said opening.

Preferably, when each flap is moved from its rst to its second position, the point of interconnection of the front flap portion and the rear ap portion slides towards the point of pivotal connection of the rear flap portion to the Xed Wall portion.

The rear ap portion may be pivotally connected to a link which is itself pivotally connected to a rearwardly displaceable member carried by the radially outer wall, rearward displacement of said member moving the ap into its second position.

The rearwardly displaceable member may comprise a fairing which covers the radially outer end of said opening, rearward displacement thereof uncovering said opening.

The said link may be also pivotally connected at a point intermediate the length thereof to the front flap portion.

The link may be connected to the front ilap portion at a point forwardly of the point of interconnection of the front flap portion and the rear flap portion.

The link may be pivotally connected to the front of the fairing.

The opening may contain yguide vanes adapted to direct the said gas forwardly when the flaps are in the said second position.

The invention also provides a gas-turbine engine having a thrust reverser as set forth above.

The gas-turbine engine may have a ducted fan, the thrust reverser being adapted to reverse the thrust produced by the ducted fan.

The invention will be described, merely by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a gas-turbine engine provided with a thrust reverser according to the present invention, and

FIG. 2 shows part of the structure of FIG. 1.

Referring to FIG. 1, a gas-turbine engine 10 has a front fan 12 disposed in a cylindrical fan cowl 14. The fan cowl encloses the upstream portion of the engine casing, to form an annular fan duct 16. The cylindrical fan cowl 14 supports the engine by means of angularly spaced apart struts 15. The duct 16 is defined by a radially inner wall 18 constituted by the engine casing, and a radially outer wall 20 constituted by the internal wall of the fan cowl. In operation of the engine, the air compressed by the fan 12 passes through the annular duct 16.

The duct fan is provided with a thrust reverser, best seen in FIG. 2. The fan cowl 14 has a circumferentially extending opening 22 in the portion thereof forming the wall 20 of the annular duct 16. The opening 22 extends around the whole circumference of the fan cowl 14, and opens to the radially outer surface thereof. When the thrust reverser is not in operation, the opening is covered at its radially outer end by a rearwardly displaceable fairing 24. The fairing is displaceable by means of hydraulic rams 26, one of which is shown in FIG. 1.

The opening 22 is closed from the annular duct 16 by means of a plurality of angularly spaced apart aps 218, which form part of the radially outer wall 20 of the duct. Each flap 28 comprises a front flap portion 30 and a rear ap portion 32. The terms front and rear are to be understood as referring to the engine, the front of the engine being on the left in FIG. 1. The front ap portion 30 has an extension arm 34 which carries at its end a roller 36. This roller is received in a slot 38 provided on the rear flap portion 32. The front iiap portion is thus interconnected with the rear ap portion for relative pivoting and sliding movement.

The rear end of rear flap portion 32 is pivotally connected at a point 40 to a fixed portion 42 of the fan cowl 14 forming part of the radially outer wall 20 to the rear of the opening 22. It will be appreciated that the portion 42 of the fan cowl 14 is supported from the front portion thereof by means of struts extending across the opening 22. These struts may conveniently be disposed between neighboring flaps 28, and may assist in closing olf the opening 22.

The rear ap portion 32 is pivotally connected at its front end 44 to a link 46. The other end of the link 46 is pivotally connected at 48 to the front of the rearwardly displaceable fairing 24. The link 46 is also pivotally connected at a point 50 intermediate its length to the front iiap portion 30 at a point on the flap portion forwardly of the point of interconnection 36 of the front flap portion 30 and the rear flap portion 32.

Within the opening 22 are cascades of guide vanes 52, to aid in directing the air passing through the annular duct 16 forwardly through the opening 22, when the thrust reverser is in operation as hereinafter described.

When the thrust reverser is inoperative, the flap portions 30 and 32 of each flap are in the positions shown in full lines in FIG. 2 (hereinafter called the iirst position), in which they close off the opening 22, allowing the air compressed by the fan 12 to pass rearwardly along the annular duct 16, providing forward thrust for an aircraft to which the gas-turbine engine is fitted.

When reverse thrust is required, the fairing 24 is displaced rearwardly by means of the hydraulic rams 26, into the position shown in dotted lines in FIG. 2, thereby uncovering the opening 22. The rearward movement of the fairing 24 causes the link 46 to pivot the rear flap portion 32 about point 40 into a second position shown in dotted lines. The link 46 also causes the front flap portion 30 to be folded in front of the rear flap portion 32, as shown 'by the dotted lines. As the flap is moved from its first to its second position, the point of interconnection of the front flap portion 30 and the rear ap portion 32, constituted by the roller 36, slides towards the point 40 of pivotal connection of the rear ap portion 32 to the fixed wall portion 42.

It will be appreciated of course that the construction and operation of each of the flaps 28 is identical.

When the flaps 28 are in their second or folded position, as shown by the dotted lines, the flaps at least partially close the annular duct 16 to the rear of the opening 22, deflecting the air compressed by the fan 12 forwardly through the opening 22, thereby producing thrust reversal. The guide vanes 52 assist in directing the air forwardly.

It will be appreciated that the gas-turbine engine is also provided with a thrust reverser for forwardly directing the gases issuing from the jet pipe thereof. This thrust reverser may be of any convenient conventional type, or it could alternatively be similar to the thrust reverser hereinbefore described. In that case, a tail bullet may be provided, in order to form the radially inner wall of an annular duct, the outer wall being formed by the engine casing.

The present invention may bring the advantage that the minimum cross-sectional area of the duct 16 when the thrust reverser is in operation is greater than if a set of single large flaps were provided and will thus avoid choking of the reverser outlet. Also, when the thrust reverser is not in operation, the annular duct 16 is not obstructed by operating mechanism of the thrust reverser such as struts or linkages extending across the duct.

I claim:

1. A thrust reverser for a gas turbine engine, comprising:

an axially extending duct adapted to have gases from the engine pass therethrough; wall structure defining said duct and having a circumferentially extending opening therein; a plurality of aps angularly spaced apart around said wall structure and having respective front and rear flap portions movable between first positions in which they close said opening, and second positions in which they extend across and at least partially close said duct to the rear of said opening, said front flap portions being disposed in front of said rear flap portions when in said second positions; and a first connection means pivotally connecting said front flap portions to their respective rear flap portions, said first connecting means having pivot points slidable along the respective rear ap portions.

2. A thrust reverser as claimed in claim 1 comprising guide vanes disposed in said opening in said wall structure and arranged to direct the gas forwardly when said flaps are in the second position.

3. A thrust reverser as claimed in claim 1 in which said Wall structure has a fixed wall portion situated to the rear of said opening, and including a second connecting means pivotally connecting said rear flap portions to said fixed wall portion.

4. A thrust reverser as claimed in claim 3 wherein the pivot points of said first connecting means which are slidable along the rear fiap portions are arranged to slide towards the points of pivotal connection of said rear flap portions and the fixed wall portion, when the flaps are moved from their first position to their second position.

S. A thrust reverser as claimed in claim 3 comprising a link for each rear ap portion, means pivotally connecting a respective rear flap portion to each link, a rearwardly displaceable member carried by said wall structure for closing the opening therein when said flaps are in said first position, and means pivotally connecting said links to said member so that rearward displacement of said member moves said fiaps into their second position.

6. A thrust reverser as claimed in claim 5 wherein said rearwardlly displaceable member comprises a fairing which covers the radially outer end of said opening in said wall structure.

7. A thrust reverser as claimed in claim 5 comprising means also pivotally connecting each of said links at a point intermediate the length thereof to a respective front flap portion.

8. A thrust reverser as claimed in claim 7 in which each link is connected to its respective front flap portion at a point forwariyof the point of interconnection of the front ap portion and the rear ap portion.

9. A thrust reverser as claimed in claim 6 wherein said links are pivotally connected to the ront of said fairing.

10. A gas turbine engine having a thrust reverser comprising: an axially extending duct adapted to have gases from the engine pass therethrough; wall structure defining said duct and having a circumferentially extending opening therein; a plurality of aps angularly spaced apart around said wall structure and having respective front and rear flap portions movable between first positions in which they close said opening, and second positions in which they extend across and at least partially close said duct to the rear of said opening, said front flap portions being disposed in front of said rear flap portions when in said second positions; and means pivotally connecting said front i flap portions to their respective rear flap portions, said connecting means having pivot points slidable along the respective rear flap portions.

11. A gas turbine engine as claimed in claim 10 having a ducted fan disposed in a fan duct, said thrust reverser fbeing disposed in said fan duct, downstream of the fan.

References Cited UNITED STATES PATENTS MARK M. NEWMAN, Primary Examiner U.S. C1. X.R. 

